The goal of this proposal is to develop a model of hemineglect - the neurological syndrome resulting from lesions in the parietal lobe - based on the response of single neurons in the parietal cortex. Such a model is an important step toward understanding the neural structure of spatial representations and their role in the control of behavior. Previous models have not attempted to relate the syndrome to the neurophysiological data obtained in behaving monkeys and, conversely, none of the neuronal models of spatial representations have been applied to hemineglect. The approach is based on the basis function theory of spatial representations. This theory, which has been recently developed, was motivated by both theoretical considerations regarding the role of parietal cortex in sensorimotor transformations and the way parietal neurons integrate sensory and posture signals. The hemineglect model combines the basis function theory with classical models of spatial attention and with anatomical constraints on the distribution of neurons across hemispheres. The long-term objective is to show that these three components are sufficient to account for the behavior of neglect patients in a wide range of tasks. Simulations focus on five issues: the line bisection test, the line cancellation experiment, the frame of reference of the deficit, object-centered neglect and recovery. It is argued that understanding spatial representations at the neural level can shed new light on some aspects of the syndrome which cannot be easily explained in psychological terms. This applies, in particular, to the temporary recovery after caloric stimulation of the vestibular system or the fact that multiple frames of reference are affected simultaneously.